JPH04267937A - Polyamide-made gas separating membrane and method of use thereof - Google Patents

Abstract

PURPOSE: To manufacture a membrane with high hydrophobicity and high proper thermal stability and having excellent gas productivity by deriving it from aromatic diacyl chloride and the specified diamines having two or more benzene rings. CONSTITUTION: The polyamide gas separation membranes have formula I (where R is formula II, Ar is formula III (Ar' is an aromatic moiety such as phenylene or naphthalene, X is a divalent group, R' is a divalent moiety)). The polyamide composition is sol. in usual org. solvents, shows relatively high hydrophobicity and furthermore, has high proper thermal stability. The polyamide membranes are usable for enriching each of oxygen and nitrogen from air for raised combustion or an inactive flow, hydrogen recovery in purification and ammonia plants, carbon monoxide separation from hydrogen in a synthetic gas system and the separation of carbon dioxide or hydrogen sulfide from hydrocarbons.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to aromatic polyamide gas separation membranes and methods for separating one or more gases from gaseous mixtures using such membranes. These polyamides are derived from a variety of aromatic diacyl chlorides, including some of those commonly used for gas separation membrane manufacture, and certain diamines having two or more benzene rings.

0002

[Prior art] U. S. Re30,351, U. S.
3,822,202 and U. S. 3,899,309
discloses gas separation membrane materials comprised of certain semi-rigid aromatic polyamides, polyimides and polyesters.

[0003]U. S. No. 3,567,632 discloses reverse osmosis membranes made of aromatic nitrogen-linked polymers.

[0004]U. S. No. 4,217,227 discloses an aromatic copolyamide reverse osmosis membrane compositionally incorporating chain-extended diamine residues.

[0005]U. S. No. 4,595,503 discloses ultrafiltration membranes made from aliphatic polyamide materials.

[0006]U. S. No. 4,627,992 discloses an ultrafiltration membrane made from aromatic polyamide.

[0007]U. S. No. 4,659,383 discloses a reverse osmosis membrane made from polyamide material.

[0008]U. S. No. 4,713,438 discloses certain polyamide compositions that incorporate chain-extended diamine residues.

[0009]U. S. No. 4,737,286 discloses a microporous polyamide membrane.

[0010]U. S. No. 4,770,777 discloses microporous membranes made from aliphatic polyamides.

EPO 219,878 discloses gas separation polyamide membrane materials compositionally incorporating heavily substituted phenylenediamine residues.

0012

SUMMARY OF THE INVENTION The present invention relates to certain polyamide separation membranes that are particularly useful for gas separation and methods of using them. Polyamide membrane materials of this type compositionally contain diamine residues with two or more aromatic units incorporated into the polymer chain. Membranes made from this type of polyamide material have improved environmental stability and excellent gas productivity. The high selectivity for several gases from multicomponent mixtures is due to optimizing the molecular free volume in the polymer. These diamines have an amino group attached to a benzene nucleus which is bridged with at least one aromatic nucleus by any of a variety of divalent groups.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compound having the structural formula H2N-Ar-
NH2 [wherein -Ar- is

[0014]

[Chemical formula 11]

##STR1## where -Ar'- is

001
6]

[Chemical formula 12]

or a mixture thereof, where -Y is independently -H, an alkyl group having 1 to 6 carbon atoms,
an aromatic group having 6 to 12 carbon atoms, or a halogen, such as -F, -Cl, Br or -I, preferably phenyl or -H, where n is 0 to 4; is an integer, and -R'- is -x-,

[0018]

[Chemical formula 13]

[0019] By manufacturing a gas separation membrane obtained from polyaramids into which diamine residues derived from diamines [0019] or mixtures thereof are incorporated, gas separation exhibiting exceptional gas permselectivity Concerning the discovery that membranes can be obtained.

[0020] Gas separation membranes made from the above-mentioned materials have a gas permeation rate and a
It has an excellent balance of selectivity for two gases. The high gas productivity of these membranes results from the incorporation of the diamine residues into this polyamide chain.
This is thought to be due to optimizing the molecular free volume in the polymer structure.

The present invention provides a highly productive polyamide gas separation membrane, of which at least 50% by weight consists essentially of repeating units.

[0022]

[Chemical formula 14]

(wherein -Ar- has the meaning defined above and -R-

[0024]

[Chemical formula 15]

[0025] is provided.

As a further advantage, the preferred polyamide compositions of the present invention are soluble in common organic solvents. This is a great advantage in that it facilitates the fabrication of industrially usable gas separation membranes. These soluble polyamides are
It can be solution cast onto a porous, solvent-resistant substrate to act as a dense separation layer in a composite membrane. Alternatively,
These can be solution cast as dense or asymmetric membranes.

[0027] Compared to the prior art polyamide compositions for gas separation membrane applications described herein, the polyamide compositions of the present invention exhibit relatively higher hydrophobicity. This is a potentially significant advantage in facilitating commercial gas separation membrane manufacturing. Complex dewatering operations for polyamide membranes are difficult to perform in the prior art, e.g. S. 4,080,743, U
．． S. 4,080,744, U. S. 4,120,09
8 and EPO 219,878. As can be appreciated by those skilled in the art, such laborious membrane dehydration operations can be greatly simplified using the more hydrophobic polyamide materials described herein.

The polyamides of the present invention have high inherent thermal stability. They are generally stable at temperatures up to 350° C. in air or an inert atmosphere. The glass transition temperature of these polyamides is generally 200°C or higher. The high temperature properties of these polyamides can help limit membrane compaction problems that occur even at intermediate temperatures in other polymers.

The polyamide membranes disclosed herein can be used in gas separation. The polyamide membranes of the present invention can be used for enrichment of oxygen and nitrogen, respectively, from elevated combustion or inerting stream air; for hydrogen recovery in refining and ammonia plants; for the separation of carbon monoxide from hydrogen in syngas systems; and the separation of carbon dioxide or hydrogen sulfide from hydrocarbons.

[0030]

[Example] Example 1 A molten mixture of isophthaloyl dichloride: terephthaloyl dichloride (molar ratio 7:3, 20.3 g, 0.10 mol) was
N-methylpyrrolidone (350 mL) under an inert atmosphere
2,2-bis[4-(4-aminophenoxy)phenyl]propane,

[0031]

[Chemical formula 16]

(41.0 g, 0.10 mol) was added dropwise into a stirring solution. The reaction temperature was maintained at 50° C. or lower by adjusting the dropping rate. After stirring this very viscous golden reaction solution for 4 hours, lithium hydroxide monohydrate (10.49 g, 0.25 mol) was added and the resulting reaction mixture was stirred at room temperature overnight. The reaction solution was diluted with additional N-methylpyrrolidone and then precipitated into water. The resulting solid was collected, washed three times with water, three times with methanol, and then air dried overnight. This solid was further heated in a vacuum oven for 20 inches (0.
51m) Mercury, dried at 120°C for 6 hours, 50.9g
of product was obtained.

The polymer prepared above was found to be soluble in m-cresol, dimethylsulfoxide, N,N-dimethylacetamide and N-methylpyrrolidone.

A 15 mil (38.4
Films of the polymer prepared above were cast at 100° C.±2° C. from a 15% polymer solution (by weight) in N-methylpyrrolidone with a knife gap of 10 −5 m). After drying on a plate at 100°C ± 2°C for 0.5 hours,
This film was further placed in a vacuum oven for 20 inches (0.
．． 51m) Mercury, dried overnight at room temperature. After peeling the film from the plate, it was dried in a vacuum oven at 20 inches (0.51 m) of mercury at 120° C. for 4 hours. The film was sticky and flexible and could be folded without cracking.

[0035] Du Pont TEFLONR dry lubricant contains fluorocarbon telomers that reduce the adhesion of membranes to glass plates.

[0036] The thickness produced above was 1.34 mils (3.4 mils).
x10-5m) film, 490.3psi
The permeability of the mixed gas oxygen/nitrogen (21/79 mol) at 26.2° C. (3380 kPa) was tested. The results are as follows: O2 productivity: 54 centibarrel (
centiBarrers) O2/N2 selectivity: 6.37.

Centibarrel is [(cubic centimeters of gas passing through the membrane at standard temperature and pressure) x (thickness of the membrane in centimeters) x 10-12] ÷ [(permeation area of the membrane in square centimeters) x (time in seconds) x (difference in partial pressure across the membrane in centimeters of mercury (cmHg)), i.e.

[0038]

[Math 1] is the numerical value.

Example 2 A molten mixture of isophthaloyl dichloride:terephthaloyl dichloride (molar ratio 7:3, 29.51 g, 0.145 mol) was added to pyridine (27.6 g, 0.35 mol) under an inert atmosphere.
mol) and 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisaniline in N-methylpyrrolidone (600 mL).

[0040]

[Chemical formula 17]

(50.0 g, 0.145 mol) was added dropwise into a stirring solution of the solution. By adjusting the dropping rate, the reaction temperature was maintained at 50° C. or lower. The resulting highly viscous solution was stirred for 1 hour at 53°C±4°C and then precipitated in water. Collect this resulting white solid,
After washing 4 times with water and 2 times with methanol, it was air dried overnight. The solid was further dried in a vacuum oven over 20 inches (0.51 m) of mercury at room temperature overnight and at 150° C. for 4 hours to yield 66.9 g of product.

A 15 mil (38.4
Films of the polymer prepared above were cast at 85° C.±2° C. from a 10% polymer solution (by weight) in N-methylpyrrolidone with a knife gap of 10 −5 m). After drying on a plate at 85°C ± 2°C for 0.5 hours, the film was further dried in a vacuum oven for 2 hours.
0 inches (0.51 m) of mercury, dried overnight at room temperature. After peeling the film from the plate, it was dried in a vacuum oven at 20 inches (0.51 m) of mercury at 120° C. for 4 hours. The film was sticky and flexible and could be folded without cracking.

[0043] If the thickness produced above is 1.0 mil (2.54
x 10-5m) film, 483.7 psi
The permeability of the mixed gas oxygen/nitrogen (21/79 mol) at 26.0° C. (3335 kPa) and 26.0° C. was tested. The results are as follows: O2 productivity: 31 cm barrel O
2/N2 selectivity: 6.6.

A 15 mil (38.4
A film of the polymer prepared above was cast at 80° C. from a 15% polymer solution (by weight) in N-methylpyrrolidone with a knife gap of x 10 −5 m). After drying this film on a plate at 80°C for 30 minutes,
Cool to room temperature and place in a vacuum oven at 20 in.
．． 51m) Mercury, dried overnight at room temperature. After peeling the film from the plate, it was dried in a vacuum oven at 20 inches (0.51 m) of mercury at 120° C. for 4 hours. It was then tested for permeability to a mixed gas H2/CH4 (50/50 moles) at 400 psig (276 x 104 Pa) and 25°C. The results are as follows: H2 Productivity: 350 centibarrel H2/CH4 Selectivity: 52.

Example 3 A molten mixture of isophthaloyl dichloride: terephthaloyl dichloride (molar ratio 7:3, 203.02 g, 1 mol) was dissolved in 4,4'-[
1,4-phenylenebis(1-methylethylidene)]bisaniline

[0046]

[Chemical formula 18]

(344.0 g, 1.0 mol) was added dropwise into a stirring solution. By adjusting the dropping rate, the reaction temperature was maintained at 50° C. or lower. The resulting very viscous, clear, yellow-brown solution was added at 2.5 mL after the final drop.
Stir for hours. Lithium hydroxide monohydrate (92.31g
, 2.2 mol) to the rapidly stirring reaction solution, and the resulting reaction mixture was stirred at room temperature overnight. The reaction solution was diluted with additional N-methylpyrrolidone and then precipitated into water. The resulting white solid was collected, washed twice with water and twice with methanol, and then air dried overnight. Further, this solid was heated in a vacuum oven for 20
Drying at 120° C. for 6 hours in mercury gave 497.7 g of product.

A 15 mil (38.4
Films of the polymer prepared above were cast at 85° C.±2° C. from a 10% polymer solution (by weight) in N-methylpyrrolidone with a knife gap of 10 −5 m). After drying on a plate at 85°C ± 2°C for 0.5 hours, the film was further dried in a vacuum oven for 2 hours.
0 inches (0.51 m) of mercury, dried overnight at room temperature. After peeling the film from the plate, it was dried in a vacuum oven at 20 inches (0.51 m) of mercury at 120° C. for 4 hours. The film was sticky and flexible and could be folded without cracking.

[0049] If the thickness produced above is 0.9 mil (2.3x
482.4 psig using 10-5 m) film
(3326 kPa) and 27.1° C. The permeability of mixed gas oxygen/nitrogen (21/79 mol) was tested. The results are as follows: O2 productivity: 60 cm barrel O
2/N2 selectivity: 6.1.

Example 4 Isophthaloyl dichloride: Terephthaloyl dichloride (70:
30) (mol) (29.51 g, 0.145 mol, molten) was dissolved in 4,4'-[1,4-phenylenebis(1 -methylethylidene)]bisaniline (50g, 0
．． 145 mol) and pyridine (27.6 g, 0.34
9 mol) into a stirring solution. The reaction temperature was adjusted to ≦40° C. by this dropwise rate. After the final addition, the reaction mixture was warmed to 50° C. for 2 hours. The highly viscous golden solution was precipitated in water and the resulting solid was washed four times with 3 liters of water and twice with 2 liters of methanol. This white solid was air-dried and then placed in a vacuum oven at 20 inches (0.51 m) of mercury at room temperature.
After drying at 150° C. for 4 hours, 66.0 g of product was obtained.

[0051] The Du Pont cell is equipped with a Du
Pont thermal analysis model 990 (baseline scope =
Differential scanning calorimetry analysis (DSC) of this polymer was performed using a heating rate of 10°C/min in a nitrogen atmosphere. A transition was observed with a starting point of 259.6°C, a midpoint of 264.7°C, and a final point of 269.8°C.

[0052] The Du Pont cell is equipped with a Du
Pont thermogravimetric analysis model 99 (in oxygen atmosphere, 10°C
Thermogravimetric analysis (TGA) of this polymer was performed using a heating rate of 0.25 min. A 5% weight loss was observed at 400°C and a 40% weight loss at 555°C.

A 15 mil (38.4
The film was prepared from a 15% polymer solution (by weight) in N-methylpyrrolidone with a knife gap of 85 m x 10 m).
Casting was done at ℃. The film was dried on a plate at 85° C. for 35 minutes, then cooled to room temperature and dried in a vacuum oven at 20 inches (0.51 m) of mercury overnight at room temperature. After removing the film from the plate, it was placed in a vacuum oven at 20 inches (0.51 m) of mercury,
It was dried at 20°C for 4 hours. 400 psig (276x1
04Pa), mixed gas H2/CH4 (50/5
0) (mole) was tested. The results are as follows: H2 productivity: 660 centibarrel H2/CH4 selectivity: 88.

Example 5 Isophthaloyl dichloride:terephthaloyl dichloride (7:3
15.14 g, 0.075 mol) was dissolved in N-methylpyrrolidone (200 mL) under an inert atmosphere.
) in 2,7-bis(4-aminophenoxy)naphthalene

[0055]

[Chemical formula 19]

(25.0 g, 0.073 mol) was added dropwise into a stirring solution of the solution. By adjusting the dropping rate, the reaction temperature was maintained at 50° C. or lower. The resulting highly viscous solution was stirred for 1 hour after the final addition and then lithium hydroxide monohydrate (10.50 g, 0.25 mol) was added. The resulting reaction mixture was stirred at room temperature overnight;
After dilution with N-methylpyrrolidone, precipitation occurred in water. The resulting white solid was collected and washed three times with water and twice with methanol. The resulting solid was air-dried overnight and then placed in a vacuum oven for 20 inches (0.51 m).
Drying at 120° C. for 5 hours yielded 34.64 g of product.

A 15 mil (38.4
Films of the polymer prepared above were cast at 100° C.±2° C. from a 15% polymer solution (by weight) in N-methylpyrrolidone with a knife gap of 10 −5 m). After drying on a plate at 100°C ± 2°C for 0.5 hours,
This film was further placed in a vacuum oven for 20 inches (0.
．． 51m) Mercury, dried overnight at room temperature. After peeling the film from the plate, it was dried in a vacuum oven at 20 inches (0.51 m) of mercury at 120° C. for 4 hours. The film was sticky and flexible and could be folded without cracking.

[0058] The thickness produced above was 1.45 mil (3.6
8x10-5m) film, 484.6ps
ig (3341kPa), 25.4℃ mixed gas oxygen/
The permeability of nitrogen (21/79 moles) was tested. The results are as follows: O2 productivity: 17 cm barrel O
2/N2 selectivity: 7.1.

Example 6 Molten isophthaloyl dichloride (23.26 g, 0.1
5 mol) in pyridine (70 mol) and N,N-dimethylacetamide (350 mL) under an inert atmosphere.

[0060]

[C20]

(49.71 g, 0.115 mol) was added dropwise into a stirred solution. By adjusting the dropping rate, the reaction temperature was maintained at 50° C. or lower. The resulting reaction solution was stirred for 3 hours after the final addition and then lithium hydroxide monohydrate (10.0 g, 0.24 mol) was added. The resulting reaction mixture was stirred at room temperature overnight and then precipitated in methanol. After soaking the resulting solid in water overnight and washing twice with water and methanol,
Air dried overnight. This solid was further heated in a vacuum oven.
Drying at 20 inches (0.51 m) mercury, 120° C. for 6 hours yielded 67.0 g of product.

A 15 mil (38.4
Films of the polymer prepared above were cast at 100° C.±2° C. from a 10% polymer solution (by weight) in N-methylpyrrolidone with a knife gap of 10 −5 m). After drying on a plate at 100°C ± 2°C for 0.5 hours,
This film was further placed in a vacuum oven for 20 inches (0.
．． 51m) Mercury, dried overnight at room temperature. After peeling the film from the plate, it was dried in a vacuum oven at 20 inches (0.51 m) of mercury at 120° C. for 4 hours. The film was sticky and flexible and could be folded without cracking.

[0063] If the thickness produced above is 1.3 mils (3.3x
483.0 psig using 10-5 m) film
(3330 kPa) and 26.4° C. The permeability of mixed gas oxygen/nitrogen (21/79 mol) was tested. The results are as follows: O2 productivity: 32 cm barrel O
2/N2 selectivity: 6.6.

Example 7 Isophthaloyl dichloride:terephthaloyl dichloride (7:3
mol, 40.60 g, 0.20 mol),
N-methylpyrrolidone (500 mL) under an inert atmosphere
Bis-1,4-(4-aminophenoxy)benzene in

[0065]

[C21]

(29.2 g, 0.10 mol) and bis-1,3-(4-aminophenoxy)benzene (29.2 g, 0.10 mol).
2 g, 0.10 mol) into a stirred solution. By adjusting the dropping rate, the reaction temperature was maintained at 50° C. or lower. To this resulting very viscous orange solution was added lithium hydroxide monohydrate (21.
0 g, 0.50 mol) was added. The resulting reaction solution was stirred for 2 hours, then diluted with additional N-methylpyrrolidone and precipitated in water. The resulting solid was soaked in water overnight, washed twice with water and methanol, and then air dried overnight. This solid was further dried in a vacuum oven at 20 inches (0.51 m) mercury at 125° C. for 5 hours.

A 20 mil (51 x 1
Films of the polymer prepared above were cast at 100° C.±2° C. from a 10% polymer solution (by weight) in N-methylpyrrolidone with a knife gap of 0-5 m). After drying on a plate at 100°C ± 2°C for 0.5 hours, the film was further dried in a vacuum oven for 2 hours.
0 inches (0.51 m) of mercury, dried overnight at room temperature. After peeling the film from the plate, it was dried in a vacuum oven at 20 inches (0.51 m) of mercury at 120° C. for 4 hours. The film was sticky and flexible and could be folded without cracking.

[0068] If the thickness produced above is 1.80 mils (4.5
7x10-5m) film, 110.2ps
The permeability of the mixed gas oxygen/nitrogen (21/79 mol) at 25.4° C. was tested at 760 KPa. The results are as follows: O2 productivity: 23 cm barrel O
2/N2 selectivity: 7.4.

Features and aspects of the present invention are as follows.

1.　　expression

[0071]

[C22]

[In the formula, -R- is

[0073]

[C23]

and -Ar- is

[0075]

[C24]

[0076] where -Ar'- is

007
7]

[C25]

or a mixture thereof; -Y is independently -H;
an alkyl group having 1 to 6 carbon atoms, an aromatic group having 6 to 12 carbon atoms, or a halogen, where n is an integer from 0 to 4, and -R'- , -x
-,

[0079]

[C26]

or a mixture thereof.

2. 1. The gas separation membrane of item 1, wherein -Y is phenyl or -H.

3. The gas separation membrane according to the second term, wherein -Y is -H.

4. -Ar’- is

[0084]

[C27]

The gas separation membrane according to item 3, which is:

[0086]

[0087]

7. -Ar- is

[0089]

[C28]

The gas separation membrane according to item 6, which is:

8. -Ar’- is

[0092]

[C29]

7. The gas separation membrane according to item 7.

[0094]

10. 9. The gas separation membrane of item 8, wherein -x- is -o-.

11.　　expression

[0097]

[C30]

[In the formula, -R- is

0099

[Chemical formula 31]

[0100] and -Ar'- is

[0101]

[C32]

0102 and -Ar'- is

[0103]

[Chemical formula 33]

or a mixture thereof; -Y is independently -H;
an alkyl group having 1 to 6 carbon atoms, an aromatic group having 6 to 12 carbon atoms, or a halogen, where n is an integer from 0 to 4, and -R'- , -x
-,

[0105]

[C34]

or a mixture thereof. How to separate gases.

12. 12. The method of clause 11, wherein -Y is phenyl or -H.

13. The method of clause 11, wherein -Y is -H.

14. -Ar’- is

[0110]

[C35]

The method of item 13, wherein:

[0112]

[0113]

17. -Ar- is

[0115]

[C36]

The method of item 16, wherein:

18. -Ar’- is

[0118]

[C37]

The method of item 17, wherein

[0120]

20. 19. The method of clause 18, wherein -x- is -o-.

Claims (2)

[Claims] [Claim 1] Formula [Formula 1] [wherein -R- is [Formula 2], and -Ar- is [Formula 3], where -Ar'- is [Formula] 4] or a mixture thereof; -Y is independently -H;
an alkyl group having 1 to 6 carbon atoms, an aromatic group having 6 to 12 carbon atoms, or a halogen, where n is an integer from 0 to 4, and -R'- , -x
-, [Image Omitted] or a mixture thereof]. [Claim 2] Formula [Chemical 6] [wherein -R- is [Chemical 7], -Ar'- is [Chemical 8], and -Ar'- is [Chemical 9] or a mixture thereof; -Y is independently -H;
an alkyl group having 1 to 6 carbon atoms, an aromatic group having 6 to 12 carbon atoms, or a halogen, where n is an integer from 0 to 4, and -R'- , -x
-, or a mixture thereof, comprising contacting the gaseous mixture with one side of a gas separation membrane made of a film-forming molecular weight polyaramid having the following properties: A method of separating at least one gas.